Simplify forecast panel and extend horizon

utils.py

@@ -29,7 +29,7 @@ def convert_str_to_date(date_str, format='%Y-%m-%d'):
 def build_forecast(values, dates, horizon_weeks=8, metric='E1RM'):
     """Build a conservative linear forecast from dated exercise observations."""
     try:
-        horizon_weeks = max(4, min(int(horizon_weeks), 26))
+        horizon_weeks = max(4, min(int(horizon_weeks), 52))
     except (TypeError, ValueError):
         horizon_weeks = 8
 
@@ -133,6 +133,7 @@ def build_forecast(values, dates, horizon_weeks=8, metric='E1RM'):
         'last_date': last_date,
         'last_value': round(float(observed_values[-1]), 1),
         'projected_value': round(float(future_values[-1]), 1),
+        'projected_change': round(float(future_values[-1] - observed_values[-1]), 1),
         'weekly_change': round(weekly_change, 1),
         'r_squared': None if r_squared is None else round(r_squared, 2),
         'confidence': confidence,
@@ -249,6 +250,7 @@ def get_exercise_graph_model(title, estimated_1rm, repetitions, weight, start_da
     observed_min_date, observed_max_date = min(start_dates), max(start_dates)
     forecast = build_forecast(estimated_1rm, start_dates, forecast_weeks, metric='E1RM') if forecast_enabled else {'available': False}
     forecast = add_top_set_forecast(forecast, weight, repetitions, forecast_target_reps)
+    forecast_horizons = [(4, '4w'), (8, '8w'), (12, '3m'), (26, '6m'), (52, '1y')]
     chart_max_date = forecast.get('end_date', observed_max_date) if forecast.get('available') else observed_max_date
     total_span = (chart_max_date - observed_min_date).days or 1
 
@@ -398,6 +400,7 @@ def get_exercise_graph_model(title, estimated_1rm, repetitions, weight, start_da
         'forecast_enabled': forecast_enabled,
         'forecast_weeks': forecast_weeks,
         'forecast_target_reps': forecast.get('selected_reps', forecast_target_reps or 5),
+        'forecast_horizons': forecast_horizons,
         'forecast_points': forecast_points,
         'forecast_band_lower': forecast_band_lower,
         'forecast_band_upper': forecast_band_upper,